What must occur before a subscriber can be re-registered?

For a subscriber to be re-registered, they must initially be registered. This is a fundamental prerequisite because re-registration implies that there was a previous registration in place. The process of re-registration is designed to update or renew the existing registration details, which cannot occur without an initial record of the subscriber's presence in the system.

Prior registration ensures that the necessary identity and credential information are already captured and stored, allowing for the appropriate checks and updates to be made during the re-registration process. If an individual has never been registered before, there would be no existing data to modify, making the re-registration process meaningless.